This is in relation to #618.

When I tried to add a custom linear solver outside of the IPOPT source tree (i.e., for use with an already installed IPOPT library), I found that headers were trying to include other headers that were not installed. The missing headers are:

• IpLibraryLoader.hpp
• IpSparseSymLinearSolverInterface.hpp
• IpStdAugmentedSystemSolver.hpp

It would be great if those could be installed.